hey! it does help, roadmarks, and interestingly it confirms what local bearing suppliers have told me, there is no
exact roller replacement for the B01 and B52 [or B40] ball bearings
comparison [roller specs from
MBS site, ball specs from
RockAuto]:
inner: 909052R - bore=32.550mm - outer dia.=72.260mm - outer race width=19.00mm
inner: B40[Ball] - bore=31.760mm - outer dia.=65.1256mm - width=19.2786mm
outer: 909001R - bore=19.057mm - outer dia.=52.832mm - outer race width=14.00mm
outer: 909067R - bore=19.057mm - outer dia.=52.832mm - outer race width:13.00mm
outer B01 [ball] - bore=19.044mm - outer dia.=52.8447mm - width=18.1102mm
lets you guys choose if you wanna make the change - with stock brakes and correct tire size, I decided there was no reason to "upgrade" something that's proved perfectly functional for 50 years

Bill